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G40.42

G40.42Cyclin-Dependent Kinase-Like 5 Deficiency Disorder

Billable / specific codeICD-10-CM

G40.42 is a billable, specific ICD-10-CM code for cyclin-dependent kinase-like 5 deficiency disorder. It is valid for submission on a claim.

Use additional code

Add a secondary code to capture the detail described below.

  • code, if known, to identify associated manifestations, such as:
  • cortical blindness (H47.61-)
  • global developmental delay (F88)

Inclusion terms

Alternative wordings a physician may use in the chart for this same code.

  • CDKL5

Risk adjustment

G40.42 risk-adjusts. Under the CMS-HCC V28 model it maps to this category:

  • HCC 201 Seizure Disorders and Convulsions0.245 RAF

Coefficient shown for the Community Non-dual Aged segment. A higher HCC in the same hierarchy will suppress this one, so capturing it does not always add score.

Medicare coverage

G40.42 is named in 10 Medicare coverage policies 10 listing it as supporting medical necessity. Which of them applies to you depends on your Medicare contractor, and coverage genuinely differs by state.

  • A56551Billing and Coding: Visual Fields Testing
  • A56612Billing and Coding: CT of the Head
  • A56619Billing and Coding: Nerve Conduction Studies and Electromyography
  • A56799Billing and Coding: Visual Fields Testing

How G40.42 is indexed

Coders do not find codes by browsing the tabular list — they look them up in the alphabetic index, under the word the physician wrote. These are the index entries that lead here, so you can see which chart wordings map to G40.42.

  • CDKL5(Cyclin-Dependent Kinase-Like 5 Deficiency Disorder)
  • DisorderCyclin-Dependent Kinase-Like 5 Deficiency(CDKL5)

Related codes at this level

Codes that share G40.4. If G40.42 is not quite right, the correct code is usually one of these.

Questions about G40.42

Is G40.42 a billable ICD-10-CM code?
Yes. G40.42 is a billable, specific ICD-10-CM code and is valid for submission on a claim.
Where does G40.42 sit in the tabular list?
Diseases of the nervous system (G00-G99), in the block Episodic and paroxysmal disorders (G40-G47).
ICD-10-CMFY2026-Apr· effective April 1, 2026

Loaded directly from the CMS/NCHS ICD-10-CM public-domain release — see data sources and our editorial policy. If this page disagrees with the CMS tabular list, this page is wrong. Reference information for professional coders; not medical or billing advice.